CN101034900B - Civil aviation ground-air communication self-adaptive disturbance restraining method based on the extraction of the blind signal and its system - Google Patents

Abstract

The invention relates to civil aviaton groud air communication self-adapting interference suppression method and its system based on the blind signal, including the following steps: translate the bi-aerial wire array received two path high frequency amplitude modulation signals into the medium frequency digital signal; and carries on the orthogonal transform after filter drawoff; changes the fact signal to the plural signal; judges the plural signal whether or not is subjected to interference, if no interference change into the six step, but change into the five step; the interference signal carries on blind extraction and cancle the signal; the one of the signal from the step four or step 5 carries on demodulate, and then filtered the high frequency noise. The invention no need uses any reference signal, using the blind self-adapting signal processing method can eliminate the interference which has a strong impact on the broadcasting station receptivity. The strong usability can suppress any form interference; and also can uses in the other communication systems, enhances the receptivity.

Description

Civil aviation air-ground communication disturbance restraining method and system thereof based on Blind Signal Extraction

Technical field

The present invention relates to a kind of double-channel self-adapting disturbance restraining method that is used for civil aviation air-ground communication.Particularly relate to a kind of raising civil aviation air-ground communication quality, ensure the civil aviation air-ground communication disturbance restraining method and the system thereof based on Blind Signal Extraction of flight safety.

Background technology

Civil aviation air-ground communication is served as the key player in the traffic control system aloft, and its stability and reliability directly affect flight safety.

According to ICAO Treaty's annex 10 I volume regulation, aloft in the traffic control, contact between ground controller and the airflight person mainly relies on VHF (very high frequency(VHF)) ground-to-plane radio to carry out, the working method of DSB-AM (band carrier wave double-sideband amplitude modulation), half-duplex operation is adopted in the radio station, its operating frequency range is 118.0MHz to 136.975MHz, channel spacing is 25KHz, and 760 communication channels can be provided, and these channels can be used in wide region again.The advantage of amplitude modulation is that band occupancy is narrow, saves frequency resource, and hardware realizes that easily therefore early stage International Civil Aviation Organization is with its standard as the earth-space communication modulation system.Though the background noise of AM receiver is very low in earth-space communication, the poor anti jamming capability of AM receiver, and existing VHF ground-air communication equipment is not all considered anti-interference problem.

Especially, along with the fast development in recent years of China Telecom's cause, the disturbed degree of civil aviaton's communication frequency is more and more serious, has had a strong impact on the flight safety of China civil aviaton.With regard to interference source, mainly contain paging centers's transmitter, high-power cordless telephone, rural f-m broadcast station, vehicle radio station etc.These interference have illegally occupied the VHF of civil aviaton communications band, have caused the aliasing to AM useful signal frequency spectrum on frequency domain.The simple band pass filter that uses can not be with its filtering; Simultaneously since the controller will with the pilot's conversation from different azimuth, so the antenna in VHF radio station approximate be nondirectional, and interference source has randomness and intellectual not, so traditional adaptive array signal treatment technology is difficult to application at this.

In the disturbance restraining method of announcing at present, in the prospectus of patent CN200410075232, mentioned the method and apparatus that suppresses disturbing pulse at AM receiver, specifically with disturbing pulse blanking from amplitude-modulated signal, after blanking, amplitude-modulated signal is carried out demodulation, carry out smooth amplitude-modulated signal remaining after the blanking.But this not too is fit to solve the problem of civil aviaton's Communication Jamming just at the impulse disturbances of short time.Once developed based on the automatic dependent surveillance of very high frequency(VHF) data chainning (ADS) system the BJ University of Aeronautics ﹠ Astronautics Technology Park, this system can carry out the interference analysis of VHF ground-to-plane radio and VHF ground-to-plane radio, the interference prediction assessment of assigned frequency in advance of pre-construction newly, thereby provides a series of for usable frequency assignment, rational.But this system has only carried out frequency preferably and pre-assignment, can not be from removing the interference of a certain frequency in essence, and be unfavorable for improving the utilance of frequency.And the speech optimization technique that adopts in the telephone system in the civil aviaton be a kind of based on one main with different location VHF voice signal frequently, two be equipped with, the voice process technologies of three emergent configurations, each road is handled in real time with the different location of frequency signal, thereby acquisition voice quality parameters, the mass parameter that obtains is compared, select Optimal Signals, produce a control signal with this, that optimum road signal of control outputs to controller's panel.There is the effect that plays the same tune on different musical instruments in the automatic dependent surveillance system of this technology and above-mentioned very high frequency(VHF) data chainning, and can ensure normally carrying out of earth-space communication to a certain extent, but all can not disturb from removing in essence, and all causes the serious waste of equipment.

Under the prerequisite that lacks prioris such as transmission channel, source signal characteristics, signal source number, Blind Source signal extraction can be used to separate or estimate in proper order one by one adaptively the waveform of source signal from the output signal of a sensor array or transducer.

Summary of the invention

Technical problem to be solved by this invention is, provide a kind of arrowband characteristics of signal in the civil aviation air-ground communication of utilizing that the instantaneous mixed model commentaries on classics of the convolution of reality is reduced to the linear instantaneous mixed model, utilization is based on the Blind Signal Extraction technology of linear instantaneous mixed model, the Adaptive Suppression that realization is disturbed the arbitrary form in the civil aviation air-ground communication, the civil aviation air-ground communication disturbance restraining method and the system thereof based on Blind Signal Extraction of raising communication quality.

The technical solution adopted in the present invention is: a kind of civil aviation air-ground communication disturbance restraining method and system thereof based on Blind Signal Extraction, and wherein method includes following steps:

(1) will be converted into digital intermediate frequency signal by the two-way very high frequency(VHF) signal that two antenna array receives;

(2) two ways of digital signals after the analog-to-digital conversion is carried out filtering extraction;

(3) signal behind the filtering extraction is carried out orthogonal transform, real signal is become complex signal;

(4) complex signal after the conversion is judged judge whether signal is interfered, if the noiseless step 6 that changes over to changes step 5 over to if having to disturb;

(5) complex signal that is interfered is carried out blind extraction, and utilize and to subdue technology the signal that has extracted is offseted;

(6) to step 4 or step 5 both one of the signal exported carry out demodulation, again through low pass filter filters out high frequency clutter.

Describedly the very high frequency(VHF) signal is converted into digital intermediate frequency signal finishes by low noise high-frequency amplifier, three grades of frequency mixers and automatic gain control circuit.

After described orthogonal transform, real signal is become complex signal, the linear convolution mixed model is converted to the linear instantaneous mixed model in complex field.

Described complex signal after the conversion is judged utilize the coefficient correlation of two paths of signals to judge, comprise the steps: to import two paths of data x1 ' and x2 '; Calculate the coefficient correlation of two paths of data; Judge whether greater than threshold value; Then carry out demodulation greater than threshold value; Otherwise the adaptive disturbance that enters based on Blind Signal Extraction suppresses platform.

Described the complex signal that is interfered is carried out the extraction of signal, and utilize and subdue technology the signal that has extracted is offseted, include Blind Signal Extraction linear convolution mixed model is reduced to the linear instantaneous mixed model; To the linear instantaneous mixed model after simplifying, adopt the Blind Signal Extraction method that mixed signal is separated; The signal and any one tunnel mixed signal that extract are sent into reduction unit, offset processing, obtain another signal.

Civil aviation air-ground communication Interference Suppression System based on Blind Signal Extraction of the present invention includes the two antenna array of received signal; The signal that two antenna array received is carried out signal processing and continuous successively radio frequency processing group, mould/number conversion group, Digital Down Convert group and orthogonal transform group; The monitor module that links to each other with the orthogonal transform group and the digital signal of its output is differentiated; The interference signal that has to monitor module output disturbs the adaptive disturbance based on Blind Signal Extraction of inhibition to suppress module; Suppress the demodulator that the interference suppression signal of module output carries out demodulation to the state no interference signal of monitor module output with based on the adaptive disturbance of Blind Signal Extraction; The D/A that links to each other with the output of demodulator is exported with the audio frequency that links to each other with D/A.

Described two antenna array, radio frequency processing group, mould/number conversion group, Digital Down Convert group are the antennas by two-way parameter unanimity, and RF processing unit, A/D converter, Digital Down Convert unit are formed.

Described radio frequency processing group includes two groups and links to each other successively: low noise amplifier, bandpass filtering amplifying circuit, one-level mixting circuit, bandpass filtering amplifying circuit, secondary mixting circuit, bandpass filtering amplifying circuit, voltage-controlled attenuator, intermediate level circuit, three grades of mixting circuits, bandpass filtering amplifying circuit, the output of intermediate level circuit also connects detecting circuit, detecting circuit and also links to each other with voltage-controlled attenuator by comparator, and three grades of mixting circuits also connect three local oscillation circuits; Wherein between two groups: three grades of mixting circuits link to each other by three local oscillation circuits, and the one-level mixting circuit links to each other by the first frequency synthesizer, and the secondary mixting circuit links to each other by the second frequency synthesizer; Low noise amplifier in two groups connects two antennas respectively, and the first frequency synthesizer also is connected crystal oscillating circuit respectively with the second frequency synthesizer.

Civil aviation air-ground communication disturbance restraining method and system thereof based on Blind Signal Extraction of the present invention, fully take into account that two or more disturb simultaneous situation few in the beechnut, and the characteristics that the signal to noise ratio of system own is higher adopt the binary channels receiving system.From the statistical independence of interference signal and useful signal, handle by the signal that the two-way receive path is received, realize the Adaptive Suppression of disturbing.At first, the present invention need not use any reference signal, adopts the blind adaptive signal processing method can offset the interference that has a strong impact on the radio station receptivity; Secondly, the present invention handles signal from the interference signal and the independence of empty signal of communication usefully, can suppress the interference of arbitrary form; In addition, utilize the arrowband characteristics of signal in the civil aviation air-ground communication that the linear convolution mixed model is converted to the linear instantaneous mixed model, simplified the complexity of Blind Source signal processing effectively.Method of the present invention is practical, cost is low.Also can be used in other communication system, improve receptivity.

Description of drawings

Fig. 1 is the used schematic diagram based on the civil aviation ground-air communication self-adaptive Interference Suppression System of Blind Signal Extraction of method of the present invention;

Fig. 2 is that employed radio frequency processing group constitutes block diagram in the inventive method;

Fig. 3 is an orthogonal transform modular structure schematic diagram;

Fig. 4 is the monitor module flow chart;

Fig. 5 is a Blind Signal Extraction modular structure schematic diagram;

Fig. 6 a is former voice signal oscillogram;

Fig. 6 b is the voice signal oscillogram of demodulation after adaptive disturbance suppresses;

Fig. 6 c, 6d are the voice signal oscillograms that two-way is subjected to the direct demodulation of interference signal.

Embodiment

Below in conjunction with the drawings and specific embodiments civil aviation air-ground communication disturbance restraining method and the system thereof based on Blind Signal Extraction of the present invention described in detail.

Civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction of the present invention is to utilize the civil aviation ground-air communication self-adaptive Interference Suppression System based on Blind Signal Extraction shown in Figure 1, comes the interference in the Adaptive Suppression earth-space communication, and concrete steps are as follows:

The first step will be converted into digital intermediate frequency signal by the two-way very high frequency(VHF) signal that two antenna array receives.The radio frequency processing group by low-noise high-frequency amplifier, three grade frequency mixer and automatic gain control circuit (in Fig. 2 empty frame part) formed of the signal that array antenna 1 and 2 receives by as shown in Figure 2, radio signal is converted into the 1.25MHz intermediate-freuqncy signal after by the radio frequency processing group, so that follow-up signal is handled.

In the present embodiment, circuit such as described low-noise high-frequency amplifier, three grades of frequency mixers and automatic gain control circuit are realized by existing circuit or principle.Three grades of intermediate frequencies that obtain after three grades of mixing are respectively 465MHz, 70MHz, 1.25MHz.

Then, two-way analog if signal implementation data to the output of radio frequency processed group is gathered and analog-to-digital conversion, thereby reduces follow-up Design of Digital Filter requirement, has adopted the scheme of over-sampling in the present embodiment, the actual sample rate of using is 5MHz, sampling resolution 12bit.

In second step, the two ways of digital signals after the analog-to-digital conversion is carried out filtering extraction.Respectively the two ways of digital signals of analog-to-digital conversion output is carried out filtering extraction by the Digital Down Convert group, data transfer rate is dropped to suitable degree from 5MSps, drop to 200KSps in the present embodiment, purpose is to improve real-time and reduce the operand that follow-up signal is handled.

The 3rd step, the signal behind the filtering extraction is carried out orthogonal transform, real signal is become complex signal.The two-way digital medium-frequency signal is carried out orthogonal transform, after the orthogonal transform real signal is become complex signal, the linear convolution mixed model is converted to the linear instantaneous mixed model in complex field.

In the 4th step, the complex signal after the conversion is judged judge whether signal is interfered, if the noiseless step 6 that changes over to changes step 5 over to if having to disturb.The surveillance of intermediate-freuqncy signal after the digitlization by as shown in Figure 4 mainly realizes whether signal be interfered and judges.

Described signal source number judge module utilizes the coefficient correlation of two paths of signals to judge, its computing formula is:

${\mathrm{\ρ}}_{x_1^{\′},x_2^{\′}}=\left|\frac{E\{x_1^{\′}\left(k\right)\·{\left(x_2^{\′}\left(k\right)\right)}^{*}\}}{\sqrt{E\left\{\right|x_1^{\′}\left(k\right){|}^2\}\·E\{\left|x_2^{\′}\left(k\right){|}^2\right\}}}\right|---\left(1\right)$

ρ wherein _{X1 ', x2 '}Be two paths of signals x _{1 '}And x _{2 '}Coefficient correlation, () ^*The expression conjugate operation, E () represents statistical expectation.

When the coefficient correlation that calculates thinks that interference is arranged during less than preset threshold, the adaptive disturbance that signal is sent into based on Blind Signal Extraction suppresses module; Think that signal is not interfered during greater than this threshold value, signal is directly sent into demodulator.Threshold value is made as one and approaches 1 number in the reality, is made as 0.9901 in the present embodiment.

In the 5th step, the complex signal that is interfered is carried out the extraction of signal, and utilize and to subdue technology the signal that has extracted is offseted.Judge the back if the earth-space communication signal is interfered through surveillance, the adaptive disturbance of then intermediate-freuqncy signal after the digitlization being sent into as shown in Figure 4 suppresses platform, utilizes self-adapting interference suppression method utilization of the present invention, improves signal interference ratio.Specifically include signal extraction unit and reduction unit.

The signal that array antenna 1a and 1b receive is that the linear hybrid of source signal different delay is the convolution mixing of source signal.

Suppose that array element 1a is the zero time delay reference array element, array element 1a, the 1b plural form that receives signal is respectively so:

$x_1\left(t\right)=a_1{\tilde{s}}_1\left(t\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f_0+f_{d1}\left(t\right))t}+a_2{\tilde{s}}_2\left(t\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{0}t}+n_1\left(t\right)---\left(2\right)$

$x_2\left(t\right)=a_1{\tilde{s}}_1(t-{\mathrm{\&tau;}}_1)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="H07157267420070518E000041.png,H07157267420070518E000043.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+f_{d2}(t-\mathrm{\&tau;}))(t-{\mathrm{\&tau;}}_1)}+a_2{\tilde{s}}_2(t-{\mathrm{\&tau;}}_2)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_0(t-{\mathrm{\&tau;}}_2)}+n_2\left(t\right)---\left(3\right)$

Wherein

With

It is respectively useful and baseband signal interference signal.f ₀Be carrier frequency.a ₁: a ₂Represent the amplitude mixed proportion of two source signals.f _D1(t) and f _D2(t) be the Doppler frequency-shift of aircraft, τ to two array elements ₁And τ ₂It is array element 1a, 1b time delay to two information sources.n ₁(t) and n ₂(t) be the receive channel noise.

But because in the VHF of civil aviaton beechnut, it is 25KHz that amplitude-modulated signal is propagated bandwidth, carrier frequency (118.00MHz～136.975MHz) very little with respect to signal, and the spacing of reception antenna is set to half-wavelength, the time delay that this moment, signal reached two antennas does not cause the variation of two antenna receiving signal envelopes, the time delay of signal between different antennae can be reduced to phase shift so, so Blind Signal Extraction linear convolution mixed model can be reduced to the linear instantaneous mixed model.Because it is closer that array element is separated by, and the flying height of aircraft is higher, and aircraft is with respect to the angle approximately equal of two array-element antenna so, so signal is the same to the Doppler frequency shift of two antennas.Known again aircraft all flies at a constant speed in the flight period in major part, so establish the constant f of the Doppler frequency of signal _d(t)=f _dBecause civil aviaton's VHF communication system has high s/n ratio, therefore in Interference Suppression System, do not consider The noise simultaneously.Then array element 1a, 1b receive the plural form of signal and are:

x(t)＝As(t) (4)

In the formula $x\left(t\right)=\left[\begin{array}{c}{x}_1\left(t\right)\\ x_2\left(t\right)\end{array}\right]$ Be the observation signal vector, $s\left(t\right)=\left[\begin{array}{c}{\tilde{s}}_1\left(t\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}({\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="H07157267420070518E000041.png,H07157267420070518E000043.png"\; state="\{\{state\}\}">f</figure-callout>}}_0+f_d)t}\\ {\tilde{s}}_2\left(t\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}{f}_{0}t}\end{array}\right],$ With

Be respectively useful and baseband signal interference signal, $A=\left[\begin{array}{cc}{a}_1& a_2\\ a_1{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j& a_2{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">e</figure-callout>}}^j\end{array}\right]$ Be hybrid matrix.Find out thus, we complex field with civil aviation air-ground communication in the model equivalence of received signal be linear instantaneous mixed model in the blind signal processing.

Below, based on the linear instantaneous mixed model after simplifying, adopt the Blind Signal Extraction method that multiple intermediate frequency digital mixing signal is separated.In separation process, satisfy quadrature constraint for making, before separation to the observation signal prewhitening:

$\tilde{x}\left(k\right)=Q{x}^{\&prime;}\left(k\right)---\left(5\right)$

Q ∈ R ^{2 * 2}Be the albefaction matrix, make $R_{\tilde{X}}=E\left\{\tilde{x}{\tilde{x}}^T\right\}=I,$ Thereby reduce the degree of freedom that hybrid matrix is estimated, also reduced the estimation difficulty of source signal simultaneously.The common method of albefaction is to use correlation matrix characteristic value decomposition, R _{X '}=E{x ' x ' ^T}=EDE ^T, wherein: E is the orthogonal matrix of relevant battle array characteristic vector, D is relevant battle array R _{X '}The diagonal matrix that characteristic value is formed.Be output as after albefaction this moment: $\tilde{x}=Q{x}^{\&prime;}=E{D}^{-1/2}{E}^T{x}^{\&prime;}.$

Described extraction unit adopts based on the MKMA of gradient (Modified Kurtosis Maximization Algorithm) at random weights is upgraded, and its iterative formula is:

w(k+1)＝w(k)+μ(k)

_wJ _MKMA(w) (6)

In the formula:

${\&dtri;}_w{J}_{\mathrm{MKMA}}\left(w\right)=-\frac{\mathrm{sgn}\left(\mathrm{CU}{M}_4\right[y_1\left]\right)}{E\left\{\right|{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H07157267420070518E000041.png,H07157267420070518E000042.png"\; state="\{\{state\}\}">y</figure-callout>}}_1{|}^2\left\}\right|\mathrm{CU}{M}_4\left[y_1\right]|}\&times;$

$\left[E\right\{\tilde{x}{y}_1^{*}\left\}\right[E\left\{\right|y_1{|}^4\}-|E\left\{y_1^2\right\}{|}^2]-E\{\left|y_1^2\right|\left\}E\right\{\left|y_1{|}^2\tilde{x}{y}_1^{*}\right\}+E\left\{\right|y_1^2\left|\right\}E\left\{y_1^{*2}\right\}E\left\{y_1\tilde{x}\right]---\left(7\right)$

Wherein μ (k) is an adaptive step, CUM ₄The fourth order cumulant of expression complex signal, $y_1\left(k\right)=w^H\left(k\right)\tilde{x}\left(k\right)$ Output for extraction unit.

With the signal y that extracts ₁Reach any one tunnel mixed signal and send into reduction unit, offset processing, obtain another signal.Described reduction unit adopts based on following energy cost function:

$J\left({\tilde{w}}_1\right)=E\left\{\mathrm{\&rho;}\left(y_2\right)\right\}=\frac{1}{2}E\left\{{\left|{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="H07157267420070518E000011.png,H07157267420070518E000041.png"\; state="\{\{state\}\}">y</figure-callout>}}_2\right|}^2\right\}---\left(8\right)$

New formula is to utilize at random gradient method can obtain more:

$\tilde{w}(k+1)=\tilde{w}\left(k\right)+u_2\left(k\right){\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H07157267420070518E000041.png,H07157267420070518E000042.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^{*}({\tilde{x}}_1\left(k\right)-\tilde{w}{y}_1\left(k\right))---\left(9\right)$

Then obtain subduing being output as:

$y_2\left(k\right)={\tilde{x}}_1\left(k\right)-\tilde{w}\left(k\right)y_1\left(k\right)---\left(10\right)$

The 6th step, to step 4 or step 5 both one of the signal exported carry out demodulation, again through low pass filter filters out high frequency clutter.The digital medium-frequency signal that adaptive disturbance is suppressed module output carries out demodulation (bag inspection), utilizes D/A (D/A) converting unit to carry out digital-to-analogue conversion, with regard to exportable audio signal clearly.

Fig. 6 a, 6b, 6c, 6d have provided the effect contrast figure who has noiseless inhibition to handle.Wherein, Fig. 6 a is former voice signal oscillogram, Fig. 6 b is the voice signal oscillogram of demodulation after adaptive disturbance suppresses, and Fig. 6 c, 6d are the voice signal oscillogram of the direct demodulation of two-way mixed signal, as seen Fig. 6 b compares more approaching former voice signal oscillogram with Fig. 6 c, 6d, show that this method is very effective, is suitable for practical application.

As shown in Figure 1, the civil aviation air-ground communication Interference Suppression System based on Blind Signal Extraction of the present invention includes two antenna array 1a, the 1b of received signal; Radio frequency processing group 2, A/D (mould/number) conversion group 3, Digital Down Convert group 4 and orthogonal transform group 5 that the signal that two antenna array 1a, 1b are received carries out signal processing and links to each other successively; The monitor module 6 that links to each other with orthogonal transform group 5 and the digital signal of its output is differentiated: the interference signal that has to monitor module 6 outputs disturbs the adaptive disturbance based on Blind Signal Extraction of inhibition to suppress module 7; Suppress the demodulator 8 that the interference suppression signal of module 7 outputs carries out demodulation to the state no interference signal of monitor module 6 output with based on the adaptive disturbance of Blind Signal Extraction; D/A (D/A) transducer 9 that links to each other with the output of demodulator 8 and the audio frequency that links to each other with D/A converter 9 output 10.

Above-mentioned two antenna array 1a, 1b, radio frequency processing group 2, A/D conversion group 3, Digital Down Convert group 4 are made up of antenna, RF processing unit, A/D converting unit, the Digital Down Convert unit of two-way parameter unanimity respectively.Their formation and effect are respectively: RF processing unit adopts general superheterodyne reception mode, and the very high frequency(VHF) received signal is changed into the fixed intermediate frequency signal; Described A/D converter adopts common analog to digital converter, transfers analog signal to digital signal; Described Digital Down Convert group adopts common digital decimation technology, data flow is at a high speed changed into the data flow of low speed.They can adopt any existing or new project organization and device to realize.Described orthogonal transform group realizes the orthogonal transform of two paths of signals respectively.

As shown in Figure 2, described radio frequency processing group 3 includes two groups and links to each other successively: LNA (low noise amplifier) 11, BPF (bandpass filtering) amplifying circuit 12, one-level mixting circuit 13, BPF amplifying circuit 14, secondary mixting circuit 15, BPF amplifying circuit 16, voltage-controlled attenuator 17, intermediate level circuit 18, three grades of mixting circuits 19, BPF amplifying circuit 20, the output of intermediate level circuit 18 also connects detecting circuit 22, detecting circuit 22 and also links to each other with voltage-controlled attenuator 17 by comparator 21, and three grades of mixting circuits 19 also connect three local oscillation circuits 23; Wherein between two groups: three grades of mixting circuits 19 link to each other by three local oscillation circuits 23, and one-level mixting circuit 13 links to each other by first frequency synthesizer 24, and secondary mixting circuit 15 links to each other by second frequency synthesizer 26; LNA circuit 11 in two groups connects antenna 1a and antenna 1b respectively, and first frequency synthesizer 24 also is connected crystal oscillating circuit 25 respectively with second frequency synthesizer 26.

Claims (8)

1. the civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction is characterized in that, includes following steps:

(1) will be converted into digital intermediate frequency signal by the two-way very high frequency(VHF) signal that two antenna array receives;

(2) two ways of digital signals after the analog-to-digital conversion is carried out filtering extraction;

(3) signal behind the filtering extraction is carried out orthogonal transform, real signal is become complex signal;

(4) complex signal after the conversion is judged judge whether signal is interfered, if the noiseless step 6 that changes over to changes step 5 over to if having to disturb;

(5) complex signal that is interfered is carried out blind extraction, and utilize and to subdue technology the signal that has extracted is offseted;

(6) to step 4 or step 5 both one of the signal exported carry out demodulation, again through low pass filter filters out high frequency clutter.

2. the civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction according to claim 1, it is characterized in that, describedly the very high frequency(VHF) signal is converted into digital intermediate frequency signal finishes by low noise high-frequency amplifier, three grades of frequency mixers and automatic gain control circuit.

3. the civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction according to claim 1, it is characterized in that, after described orthogonal transform, real signal is become complex signal, the linear convolution mixed model is converted to the linear instantaneous mixed model in complex field.

4. the civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction according to claim 1, it is characterized in that, described complex signal after the conversion is judged utilize the coefficient correlation of two paths of signals to judge, comprise the steps: to import two paths of data x1 ' and x2 '; Calculate the coefficient correlation of two paths of data; Judge whether greater than threshold value; Then carry out the D/A conversion greater than threshold value; Otherwise the adaptive disturbance that enters based on Blind Signal Extraction suppresses platform.

5. the civil aviation air-ground communication disturbance restraining method based on Blind Signal Extraction according to claim 1, it is characterized in that, the described extraction of the complex signal that is interfered being carried out signal, and utilize and to subdue technology the signal that has extracted is offseted, include Blind Signal Extraction linear convolution mixed model is reduced to the linear instantaneous mixed model; To the linear instantaneous mixed model after simplifying, adopt the Blind Signal Extraction method that mixed signal is separated; The signal and any one tunnel mixed signal that extract are sent into reduction unit, offset processing, obtain another signal.

6. the civil aviation air-ground communication Interference Suppression System based on Blind Signal Extraction is characterized in that, includes the two antenna array (1a, 1b) of received signal; Radio frequency processing group (2), mould/number conversion group (3), Digital Down Convert group (4) and orthogonal transform group (5) that the signal that two antenna array (1a, 1b) is received carries out signal processing and links to each other successively; The monitor module (6) that links to each other with orthogonal transform group (5) and the digital signal of its output is differentiated; The interference signal that has to monitor module (6) output disturbs the adaptive disturbance based on Blind Signal Extraction of inhibition to suppress module (7); Suppress the demodulator (8) that the interference suppression signal of module (7) output carries out demodulation to the state no interference signal of monitor module (6) output with based on the adaptive disturbance of Blind Signal Extraction; D/A (9) that links to each other with the output of demodulator (8) and the audio frequency that links to each other with D/A (9) output (10).

7. the civil aviation air-ground communication Interference Suppression System based on Blind Signal Extraction according to claim 6, it is characterized in that, described two antenna array (1a, 1b), radio frequency processing group (2), mould/number conversion group (3), Digital Down Convert group (4), be antenna, and RF processing unit, A/D converter, Digital Down Convert unit are formed by two-way parameter unanimity.

8. according to claim 6 or 7 described civil aviation air-ground communication Interference Suppression Systems based on Blind Signal Extraction, it is characterized in that, described radio frequency processing group (2) includes two groups and links to each other successively: low noise amplifier (11), bandpass filtering amplifying circuit (12), one-level mixting circuit (13), bandpass filtering amplifying circuit (14), secondary mixting circuit (15), bandpass filtering amplifying circuit (16), voltage-controlled attenuator (17), intermediate level circuit (18), three grades of mixting circuits (19), bandpass filtering amplifying circuit (20), the output of intermediate level circuit (18) also connects detecting circuit (22), detecting circuit (22) also links to each other with voltage-controlled attenuator (17) by comparator (21), and three grades of mixting circuits (19) also connect three local oscillation circuits (23); Wherein between two groups: three grades of mixting circuits (19) link to each other by three local oscillation circuits (23), and one-level mixting circuit (13) links to each other by first frequency synthesizer (24), and secondary mixting circuit (15) links to each other by second frequency synthesizer (26); Amplifier circuit in low noise in two groups (11) connects antenna (1a) and antenna (1b) respectively, and first frequency synthesizer (24) also is connected crystal oscillating circuit (25) respectively with second frequency synthesizer (26).

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